1. Field of the Invention
The present invention relates to a hybrid storage device and related computer system and control method, and more particularly, to a hybrid storage device capable of flexibly expanding various storage devices and related computer systems and control method.
2. Description of the Prior Art
A storage device is one of the most important components in a computer system. The storage device is utilized for retaining various digital data or application programs for computing uses. A conventional hard disk drive (HDD) offers advantages of low cost and rapid writing speed, and therefore, is one of the popular types of storage devices. However, during a data access process, both high speed rotation of platter and frequent move operations of the read-write head may consume a lot of electrical power and need much operational time to access the required data. In other words, because the reading speed of the HDD is too slow, the execution efficiency of the whole computer system will be degraded when the traditional HDD is used for storing system initiation data in a boot-up process, resulting in a long boot-up time and causing inconvenience.
Compared with the traditional HDD, a solid state drive (SSD) produced with semiconductor based manufacturing processes applies an electrical reading and writing scheme without any moving parts and also has advantages of low power consumption and quick data access. However, the drawback of the SSD is that it is more expensive than the traditional HDD and has a limited lifetime (limitation in the number of write/erase cycles) so that the SSD is not going to entirely replace the HDD in the computer system soon.
Thus, the prior art provides a hybrid storage device combining the traditional HDD with the SDD to apply in the computer system. Please refer to FIG. 1, which is a schematic diagram of a hybrid storage device 10 according to the prior art. The hybrid storage device 10 includes a disk controller 102, an SSD 104, and a HDD 106. The SSD 104 and the traditional HDD 106 communicate with the disk controller 102 via serial transmission interfaces 108 and 110 respectively. The disk controller 102 exchanges data with a south bridge circuit of a computer system via a serial transmission interface 112. In the hybrid storage device 10, the computer system can apply various storage devices through the control of the disk controller 102. For example, during data storage, the HDD 106 is used for writing data; meanwhile, the data can also be synchronized to the SSD 104. During reading data, the disk controller 102 controls the reading of data to be from the SSD 104. Therefore, during the boot-up process, the computer system can read the required application program from the SSD 104 and carry out the initiation of operating system without waiting for reading data stored in the HDD 106. Accordingly, the hybrid storage device 10 can reduce power consumption of boot-up process and improve the boot-up speed. On the other hand, the prior art can also enhance the access speed of the storage device through a software design for shortening the boot-up time.
For a conventional hybrid storage device, the SSD and the traditional HDD are usually disposed on the same hardware unit. In such a condition, a user can only use the integrated hybrid storage device without performing any expanded configuration. In other words, the user must purchase the above-mention conventional hybrid storage device even though the user already has a traditional HDD. As a result, a user having an upgrading requirement must spend extra upgrading money to realize the hybrid storage device purpose. In addition, if the prior art utilizes the software design manner to enhance the access speed of storage device, the system load of the computer system will be increased substantially. Therefore, taking the extra cost into consideration, the conventional hybrid storage device is not suitable for the user already having traditional hard disk drive.